Landing Page Needed -Convertion Rate Guarantee Required-

I need someone to create a landing page for me and as i have mentioned in the title, i need the partner to guarantee convertion rate in %.

I will sell ebook on that landing page, the book is about preparing for some exam (e.g. TOEFL, GRE, GMAT, etc.)

The target audience is clear and my target audience is ready to spend some money on the book that will help them pass the exam which is very important for their career or education.

I will advertise on adwords, adcenter and facebook.

I am ready to pay 100USD for that landing page, when its completed and does promised convertion.

I will pay 25USD when initial prototype is ready and pay next 25USD when we reach 5% convertion rate in our tests.

I will pay remaining 50USD when in our tests we reach the promised convertion rate. (I want it to be around 20%)

I am aware about your hard work and I want to pay real hard working people, not someone who wants to copy a landing page from somewhere and resell it to me, then get away with my money. Thats why i demand convertion rate guarantee.